Great Barrier Reef Region Guide

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Marine Stingers

Marine stingers, box jellyfish, Annoyus whenhottis, call them what you like, but they are now very much a hot topic.

In recent times the public have been informed that it's not safe to swim in the ocean off Port Douglas and other Tropical North Queensland towns during the wet (and now also called 'stinger') season. But if you ask an old timer, some will say "whats the big deal? As kids we used to swim all year round".

So are there more stingers now? A lot of people think so and there are arguments both for and against. The short answer from the local James Cook University... "We just do not know."

Is it simply that nowdays there is a lot more awareness of marine stingers than in the past, so are we disillusioned into thinking that there are more around?

One true blue story follows the reduction of dingo numbers over time to an increase in feral pigs, saying they love to dig up and eat turtle eggs therefore reducing the number of turtles that feed on the jellyfish.

There is some weight to this theory. The sea turtles are a major predator of the jellyfish and they have little to no side effects from the stingers lethal venom, eating tentacles and all. Turtle numbers have reduced dramatically, but more because of human hunting and habitat loss. Several fish species also feed on the jellyfish.

The most significant predatory influence probably occurs whilst the box jellyfish are in their small polyp phase in estuaries and amongst mangroves. Throughout the dry season the polyps will bud into more polyps. These polyps are eaten by juvenile and small fish species.

One argument suggests that the by-catch from previous prawn trawling techniques of predominately small fish at up to eight tones per one tone of prawns has led to more polyps reaching the jellyfish stage. The reduction of fish stocks in general, whether from commercial or recreational strains will have affected their relative threat from predators.

Another argument suggests that global warming and increased water temperatures actually benefits the jellyfish leading to larger numbers. This may yet prove to be quite the opposite.

At the end of the day much is still speculative. It wasnt until the early 1980s that the life cycle of the large, native box jellyfish, Chironex Flecferi, was known. As for the group of tiny Irukandji Syndrome jellyfish, very little is known at all, some of them are not yet even described. Around the world only one species of Irukandji (from Hawaii) have their life cycle known to science.

What the experts research does show, is that the numbers of stingers present from year to year can vary enormously! They do not yet know what causes these variations but the population overall is considered stable.

In recent years it is acknowledged that more people appeared to be stung by box jellyfish, but this is thought to be relative to the increase in numbers of people living and visiting the tropical north, and more water based activities being undertaken.

If you do want to risk the ocean waters heres a few considerations:

- The box jellyfish prefer calm, shallow waters with a gentle sloping, sandy bottom. In Port Douglas, the southern end of Four Mile Beach to Yule point is ideal habitat and considered a hot spot for researchers. Stinger nets provide some protection and are monitored by Surf Live Saving volunteers. In Port Douglas, the stinger net at the northern end of Four Mile Beach is utilised during the summer months.

- The Irukandji group is mainly found offshore and around coral reefs, however after a week or so of north easterly breezes onshore currents push them towards the shoreline in congregations. Stings have been recorded for all months of the year.

- For both types its serious if you're stung. A lot of stinging cells will be on you but only some will of fired first up, the others will with time. Vinegar does help. It will deactivate the unreleased cells stopping any more venom from entering. In Port Douglas, vinegar stations are located at intervals along Four Mile Beach. (Editor)

Whatever your opinion is, this is sure to be a subject that will continue to generate skeptics & experts. Doubt about. Is it safe to enter the water?